Spinal anesthesia

SPINAL ANAESTHESIA

1. SPINAL ANESTHESIA Moderator : Dr.Trivikram Shenoy Presentor : Dr.Shaik Tahoor Dr.Naveen Kumar Ch

2. Technique Approaches Indications and contraindications Complications and its prevention and treatment

3. Technique F our P's preparation , position , projection and puncture.

4. Preliminary Duties Preparation of the equipment and drugs for subarachnoid injection I.V access-wide bore cannula is secured and fluids bolus is given Emergency drugs and e quipment for G.A Sedation if needed Vitals recorded NIBP/SPO2/ECG Verbal contact with patient

5. Spinal needles Types Dura cutting: Quincke-babcock & pitkin needle Dura separating: whitacre & sporte sizes 16 to 30 g size Gauge of SN and colour coding 18 G – Pink 25 G – Orange 19 G - Ivory 26 G - Brown 20 G – Yellow 22 G - Black 23 G –Blue

6. All needles should have a tightly fitting removable stylet that completely occludes the lumen to avoid tracking epithelial cells into the subarachnoid space . Check for stiffness,flexibility ,resistance

7. Quincke -Babcock Spinal Needle It is considered standard spinal needle Consists of a small hub and sharp point with a medium length cutting bevel. There is fitted stylet with a matching bevelled tip to cannula point and connector Different lumen sizes ranging from 18 to 26 Most are 3.5 to 4 inches in length

8. Whitacre needle Sharp pencil point type of bevel No cutting edges Orfice on one side 2.5mm proximal to tip Saperates the fibres Cannot easily feel a give or snap Exit port smaller than lumen,so great resistance is noted while giving the drug

9. Sprotte needle It is a side-injection needle with a long opening . It has the advantage of more vigorous CSF flow compared with similar gauge needles . However, this can lead to a failed block if the distal part of the opening is subarachnoid (with free flow CSF), the proximal part is not past the dura, and the full dose of medication is not delivered

10. PITKIN NEEDLE-it is very sharp point bevel with cutting bevel GREENE NEEDLE-it is rounded ,medium length non cutting edges to bevel

11. The use larger needles improves the tactile sense of needle placement. The use of small needles reduces the incidence of post–spinal puncture headache. Multiple punctures increase the incidence of headaches. Conical-tipped needle have lesser incidence of post spinal headache. Poorly matched stylet has the potential to tear the dura matter,increase leakage

12. Position LATERAL DECUBITUS -Most common position The Spinal canal should be on a horizontal plane. The thighs flexed on their abdomen, and their neck flexed to allow the forehead to be as close as possible to the knees

13. Considerations for differences in body built b/n males and females for achieving horizontal level

14. SITTING POSITION- The Spinal canal should be on a vertical plane. stool can be provided as a foot rest and a pillow placed in the lap. flexing the patient's neck and arms over the pillow to open up the lumbar vertebral space. Recommended for Obese patients Saddle block anaesthesia Inability to adequately curl up

15. PRONE JACKKNIFE POSITION- This position is appropriate for rectal, perineal , or lumbar procedures where the position of surgery is same as that of anesthesia most often paramedian approach is used . The anesthesiologist may have to aspirate for CSF because CSF pressure is minimized when insertion of the lumbar needle is carried out in this position.

16. Classification of Technique Single injection technique hyperbaric/isobaric/hypobaric Continous injection methods intermitent -fractional differential block continous drip Segmental technique

17. Single injection technique Hyperbaric technique : It is the most commonly used method Solutions: 0.5 % to 0.75% bupivicaine in 8.25% dextrose Density-1.0190 , Specific gravity-1.0257 Each ml contains 5mg of bupivacaine 0.5%Tetracaine -5D,5%lignocaine -5D, 5%procaine(50mg)

18. Isobaric technique Tetracaine 20mg in 4ml of saline 0.5%Bupivicaine in normal saline Useful for lower abdominal surgery and perineal surgery

19. hypobaric technique Tetracaine 0.1% in distilled water Dibucaine 1:1500 in 0.5% saline Useful in prone position surgery

20. Adjuvants of S.A Opioids produce intense visceral analgesia and prolong only sensory blockade. Sites of action : the second and third laminae of the substantia gelatinosa in the dorsal horn of the spinal cord. Lipophilic agents such as fentanyl and sufentanil have a much more localized effect ,rapid onset of action and an effective duration greater than 6 hours. Examples Fentanyl-10 to 25ug Sufentanil-2.5 to 10 ug

21. Adjuvants of S.A CLONIDINE-alpha 2 agonist (150ug) Onset -same; Duration-prolonged Epinephrine- vasoconstrictor action (1:10,000) delays absorption of local anesthetic Phenylephrine-1:1,000 concentration No changes in systemic circulatory activity

22. Safe Spinal Technique Scrub hands according to aseptic surgical technique. Use sterile gloves. Avoid contaminating the spinal drug. Use aseptic technique when opening tray . Touch only sterile articles once gloved. Cleanse the skin prior to needle puncture. Avoid repeated traumatic punctures .

23. Safe Spinal Technique Do not do spinal puncture if the patients bleeding parameters are increased. Never insert a needle through an infected area. Use Local Anaesthetics in standard concentrations. Paint the patients back with antiseptic solution over the lumbosacral spine and iliac crests and drape the back.

24. S teps Find the widest interspace. The palpating fingers should identify the interspinous area and the midline A subcutaneous skin wheal is developed over this space using LA; usually 2% Lignocaine . With spinal needle leaving stylet in place with its bevel parallel to the longitudnal axis is advanced steadily and smoothly until the characteristic change in resistance

25. Steps The stylet is then removed and observe for the free flow of CSF. If it does not, the needle should be advanced a few millimeters and rechecked . If CSF still has not appeared and the needle is at a depth appropriate for the patient, the needle should be withdrawn and the insertion steps should be repeated .

26. Injection of drug- Bromage grip Stabilise the needle and attach syringe by grasping the hub with thumb and fore finger and remaing fingers against pt back to provide support. Aspirate small quantity to check the needle position. Given @0.2ml/sec Remove syringe and check for the flow of csf after giving the drug Remove the spinal needle and make the pt in prone position

27. SEQUENCE OF BLOCK 1.Sympathetic nervous system fibers (B fibers: vasodilation, skin temp ↑ ) 2.Temperature & pain conduction (A delta & C fibers) 3.Proprioception & touch (A γ & A β fibers) 4.Motor function ( A alpha fibers)

28. Approaches Mid line approach Paramedian approach Taylor’s approach

29. Mid line approach Technique of first choice. Prerequisites Minimize lumbar lardosis Access Subarachnoid space between L 2-3 , L 3-4 , L 4-5 . Structures pierced are Skin , subcutaneous tissue, supraspinous ligament , interspinous ligament , lagementum flavum , dura mater , subdural space , arachnoid matter, subarachnoid space

30. Paramedian approach The palpating fingers should identify the caudal edge of the cephalad spinous process, skin wheal is raised 1 cm lateral and 1 cm caudal to this point . The spinal needle is inserted 10 to 15 degrees off the sagittal plane in a cephalomedial plane . Structures piered are Skin , subcutaneous tissue, interspinous ligament , lagementum flavum , dura mater , subdural space , arachnoid matter, subarachnoid space

31. Paramedian approach

32. Taylors approach A variation on the para median approach. This technique is carried out at the L5-S1 interspace, the largest inter laminar interspace of the vertebral column. A skin wheal raised 1 cm medial and 1 cm caudad to the lowermost prominence of the posterior superior iliac spine . A 5-inch spinal needle is inserted in a cephalomedial direction into the subarachnoid space.

33. Taylors approach

34. Recent advances Continous injection methods: Lemmon technique-flexible spinal needle , Tuohy technique- cathetor inserted Continous drip methods: Differential block method: selectively block different modality of sensation and motor activity Segmental method: tetracaine is used Anesthesia by true volumetric displacement.

35. Indications and selection of patient Location and nature of operation- Lower limb surgery,Lower abdominal surgery,Urological & gyneacological procedures Attitude-cooperative Age-15to70 yrs Medical derrangement - HTN tolerate well lung ,liver, kidney disease better subject for spinal anesthesia Obsteric – can be given for Caesarian section

36. Indications and selection of patient Renal failure pts –well tolerated onset of analgesia is rapid Due to greater generalised acidity in uremic pts base form of local drug rapidly converts to cation form and enhances the interaction with receptor site in sodium channel mean spread of sensory block is higher duration of analgesia is shorter Due to increased fluid volume&hyperdynamic circulation in CSF

37. Other uses Paralytic Ileus(non obstructive )- contraction of gut occurs and gases expelled Hyperthyroidism enhanced adrenal gland secretions occur block given upto t5 level is beneficial for thyroid surgery Pulmonary edema - caused by htn and atheroslerotic heart disease s.a diminishes venous return and relieves cardiac load Megacolon-hirschprungs disease Pain evaluation-to know somatic or sympathetic orgin

38. Contraindication CNS causes-brain tumours,cns syphilis,meningitis and infection PNS causes- poliomylietis,multiple sclerosis demylinating diseases Circulatory causes- hypovolemia,severe anemia,shock CVS causes- hypotension,coronary diseases,aortic valvular diseases,cardiac decompensation Infections-local infection,systemic sepsis

39. Contraindication Anatomical deformity-spinal anomalies,scoliosis,metastasis to vertebrae, Special intra abdominal conditions-raised intra abdominal pressure , chronic intestinal obstruction Psychological condition-uncooperative pt , mentally disturbed pts Anticoagulant therapy- pts who are on heparin it is better to check bleeding parameters before giving spinal anesthesia

40. INTRAOPERATIVE COMPLICATION HYPOTENSION : diagnosis is established when a 25% fall in systolic pressure occurs Symptoms: related to tissue hypoxia First effects are of stimulation,apprehension,restlessness,diziness, tinnitus,headache Followed by retching, vomting Later include depression, drowsiness,disorientation,coma

41. Clinical features: Higher the level of anesthesia more is the chance of going to hypotension Umbilical level is the critical level,when it goes beyond this level there is progressive loss of capacity for reflex compensation

42. mechanism Paralysis of sympathetic vasoconstrictor fibres to arterioles Dilation of peripheral veins and venules leading to pooling of blood Paralysis of intercostal muscles leading to decreased minute volume leading to hypoxia Prophylactic dose of mephentaramine or ephedrine can be administered at the time of sucessful tap

43. treatment Head down position i.v fluids Administration of o2-mainly to increase the o2 content of circulating blood because if there is slowing of circulation in tissues and wide av o2 difference Recommended for all High spinal anesthestic pts to given suppliment o2 to minimize hypoxia,relieve dyspnea, nausea and vomiting Key stone to therapy of hypotension is vasopressor therapy

44. vasopressor therapy Ephedrine sulphate-10 to 50 mg c.o increases Mephenteramine Phenylephrine-0.5 to 1mg arteriolar constriction Epinephrine-increases hr,sbp lowers dbp,pvr Norepinephrine-increases both sbp and dbp

45. Choice of vasopressor agent We should choose the agent that combines both alpha and beta cvs effects First choice is ephedrine Second choice is mephenteramine

46. Spinal hypotension in obsterics Aorto caval compression-supine hypotension combined with inadequate hemostatic circulatory adjustments for venous return to lower extremeties Venous return depends on iliolumbar viens and vertebral plexus of azygous veins Rx: Left uterine displacement,Hydration with crystalloids, Vasopressors ephidrine / mephenteramine

47. Respiratory impairment -occurs when high spinal level is reached Rx:Treatment:suppliment o2,airway,ventillatory support if necessary Affective dyspnoea - When level of block is higher thoracic level pt may complain of breathlessness , It is due to lack of propioception Rx-encouraging the patient to voluntary take deep breathes,suppliment o2,inhaling smelling salts Nausea and vomiting: usually the result of hypotension or unopposed vagal stimulation

48. Traumatic spinal puncture - repeated attempts to achieve spinal tap may result in direct trauma to nerves,periosteum,intervertebral discs errors-failure to maintain mid line,advancement too far,blood tap,failure to recognize penetration of dura

49. High and Total spinal Occurs after excessive cephalic spread of the local anaesthetic SYMPTOMS- Unconsciousness, apnea and hypotension Treatment-symptomatic o2 inhalation, iv fluids ,ventilator may be required

50. Cardiac arrest If the block progresses (High Spinal) to the mid thoracic region involving the heart. Usually due to hypoxaemia <85% without obvious changes in respiration and cyanosis . Use of fentanyl,can account for bradycardia and arrest Incidence is commoner in young healthy adults Preceded by bradycardia Treatment-conventional doses of atropine and ephedrine is given Full resuscitation dose of epinephrine is given

51. Post operative complications Urinary retention Local anesthetic block of S2-S4 root fibers decreases urinary bladder tone and inhibits the voiding reflex Foleys cathetor may be required to insert

52. Post- dural Puncture Headache First documented by august beir in 1899 character: in the order of frequency constriction band arround head which is generally occipital or at vertex , dull ache,heaviness and pressure in the head, thrombing sensation, Spasm and pain in neck muscles,occular pain,diziness may accompany the headache It is aggravated in erect posture and relieved in supine posture

53. Differential diagnosis PDPH Coincidental headache-headache when investigated is similar to the previous headache experienced by the patient.It is not influenced by posture. Spinal headache:it is postural in nature and may occurs within 48 hours of giving spinal anesthesia Caffeine withdrawl headache:patient who consume caffeine containg beverages are likely to suffer as abstinence syndrome if intake is stopped.symptoms develop within 24 hours and typically headcache,sleeplessness,inactivity and irritability.

54. PDPH Onset:usually appears in second and third post operative day and usually subside at the end of 7 to 10 days Sex:it more frequent in young females Age :the greatest frequency of headache occurs in the age group 20 to 40 years

55. pathophysiology Due to imbalance in the csf dynamics Loss is greater than the fluid production Loss greater than 30 to 50 ml is critical to produce headache Traction of pain sensitive structures and blood vessels occur in brain resulting in headache

56. prevention Proper hydration Use introducer Use of smaller size pencil point whitacre needle Bevel parellel to longitudnal axis Early ambulation

57. treatment Psychological support and reassurance of recovery Large volume of fluids Oxygen inhalation Analgesics –aspirin Caffeine sodium benzoate-causes cerebral vasoconstriction

58. Severe cases When above measures fail EPIDURAL BLOOD PATCH is done Technique: Patient is positioned and the lumbar area is aseptically prepared for epidural puncture 8 to 10ml of venous blood withdrawn from antecubital vein

59. Epidural puncture is performed at the orginal site of puncture Blood is slowly injected @1ml/sec Pt kept in supine for 1 hour Afterwards movement and ambulation is encouraged

60. Mechanism of relief Immediate pressure effect which compress the dura matter which increases sub arachnoid pressure and restores csf dynamics Sealant effect: injected blood forms gelatinous patch over the puncture site lasting for 3-4 days allowing healing of puncture hole

61. Backache usually benign, mild and self-limited, can be treated with NSAIDs, It may be a clinical sign of a more serious complication such as epidural hematoma or abscess

62. Infection Cutaneous abscess Epidural abscess Septic meningitis Causes result from contamination of agent,inadequate sterlization,or introduction of needle through infected tissue Psuedomonas is the frequent organism Treatment:antibiotic therapy

63. Cranial nerve disturbances Most commonly involve sixth nerve Since the function is to rotate the eye ball internal strabismus occurs leading to visual disturbances blurring , diplopia,difficulty in focussing Occuring in the 6 to 8 th post operative day is peculiar to SA Men are more frequently involved Symptoms are unilateral and generally on right side Rx:Symptomatic,supine position,eye patch is helpful

64. Transient neurologic symptoms (TNS) Characterized by back pain radiating to the legs without sensory or motor deficits , occurring after the resolution of the block ; usually resolves spontaneously within several days; pathogenesis is unclear Most common with hyperbaric lidocaine and after surgery in lithotomy position

65. Meningismus Aseptic or chemical meningitis Occurs suddenly and usually in 3 or 4 th operative day It presents as intense splitting headache,stiff neck,positive kernig,photophobia,confusion and vomting Usually subside with use of aspirin and antibiotics

66. Cauda equina syndrome Suspected when pt fail to regain motor power of limbs at usual time after spinal anesthesia Symptoms: incontinence of feaces with anal sphincter paralysis,urinary retention,loss of proper function of lower extremeties Return of function is usually slow and bladder drianage is recommended as an early form of therapy

67. Myelitis Its an inflammatory reaction of medullary cord Causes : bacterial infection or effect of anesthetic drug on mylein substance apparently after the primary effects of spinal anesthesia wear off,a pronounced paraplegia of flaccid type develops with loss of sensibility If fatality occurs PM examination shows demyelination of medulla and posterior roots